A number of polycatechol chelating agents have been prepared using the 2,3-dihydroxybenzoyl (DHB) group or derivatives of it in which the benzoic acid ring has been substituted at the five position by -SO3- or at the four position by -CO2-. In each case the DHB groups are appended to a polyamine backbone. To date, linear triamines (such as spermidine), 1,3,5,-triaminomethylbenzene, and the tripod amine triaminoethylamine have all been used as molecular skeletons. During the next year we intend to continue to explore the synthesis of 4-carboxyl-substituted derivatives of DHB in tricatechol chelating agents. Depending upon the results of animal tests, attempts will be made to optimize the geometries of these complexes through variation of the backbone structure. We also plan to explore new molecular architectures for ferric chelating agents, and examine the thermodynamic properties of those prepared to date.